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Re: 800psi enough for manual disc brakes ? [Re: brads70] #1290816 11/01/13 06:20 AM 11/01/13 06:20 AM
Joined: Jan 2003 Posts: 3,575 The Netherlands BigBlockMopar master
BigBlockMopar master Joined: Jan 2003 Posts: 3,575 The Netherlands	On my own Dart I've recently replaced a set of old stock metallic pads for a set of Hawk HPS pads and the difference is verry noticable at moderate to high speeds. Not so much at low speeds with less pedalpressure. I also think these pads get better when warmed up a bit. The first few brake stops in the morning aren't that impressive. The previous pads (found on a old car), while braking was OK, mainly did a good job of polishing the rotors to a mirror shine, while the HPS pads now leave a mat finish on the rotors, also telling me they're doing a better job of grabbing the rotor. BigBlockMopar.com

Re: 800psi enough for manual disc brakes ? [Re: BigBlockMopar] #1290817 11/01/13 06:38 AM 11/01/13 06:38 AM
Joined: Aug 2004 Posts: 214 Hamburg / Germany D Den300 enthusiast
Den300 enthusiast D Joined: Aug 2004 Posts: 214 Hamburg / Germany	I noticed the same. The yellow stuff pads srubbed more off the rotors within 600miles than the ssbc ones within 4 years! They also get better when they are warm. Hamburg/Germany 69 Chrysler 300 446cui Dual Quad 12.64 @ 110.7

Re: 800psi enough for manual disc brakes ? [Re: Den300] #1290818 11/01/13 09:15 AM 11/01/13 09:15 AM
Joined: Oct 2003 Posts: 21,345 Marysville, O-H-I-O 70Cuda383 Too Many Posts
70Cuda383 Too Many Posts Joined: Oct 2003 Posts: 21,345 Marysville, O-H-I-O	Once you guys get some miles on these set-ups, I'd like to know what your rotor life is like with these more aggressive pads. Photobucket sucks

Re: 800psi enough for manual disc brakes ? [Re: 70Cuda383] #1290819 11/01/13 02:15 PM 11/01/13 02:15 PM
Joined: Jan 2003 Posts: 3,575 The Netherlands BigBlockMopar master
BigBlockMopar master Joined: Jan 2003 Posts: 3,575 The Netherlands	I drive my car daily. Although I don't travel a lot of miles every week due to the short local distances in my country, my car does do a lot of stop&go driving. BigBlockMopar.com

Re: 800psi enough for manual disc brakes ? [Re: 70Cuda383] #1290820 11/01/13 09:57 PM 11/01/13 09:57 PM
Joined: Jan 2009 Posts: 813 Ontario,Canada brads70 super stock
brads70 super stock Joined: Jan 2009 Posts: 813 Ontario,Canada	Quote: Once you guys get some miles on these set-ups, I'd like to know what your rotor life is like with these more aggressive pads. Had mine on for 3 seasons now, so far so good. I drive it to Carlisle every year and lots of local shows. Take it out almost daily if weather is good. I'm going to get a set for the rear brakes too as I found while doing the Hotchkis autocross thing at Carlisle the fronts lock up way before the rears when they get hot.

Re: 800psi enough for manual disc brakes ? [Re: brads70] #1290821 07/03/14 04:45 PM 07/03/14 04:45 PM
Joined: Sep 2007 Posts: 876 Arizona PolyDart super stock
PolyDart super stock Joined: Sep 2007 Posts: 876 Arizona	I'm bringing this thread up from the dead because I am having the same issue, but for a seemingly different reason. I am also running a proportioning valve in my rear brake line and I thought that the original poster's fix would be a "voila" moment for me, but no amount of proportioning valve adjustment will give me more than 800psi to the front brakes. The rear brakes are also at 800 psi when allowed to get full flow from the valve. I have played with the pedal ratio. The stock M/C pickup point is 1.5" below the pivot. The hole I drilled is 2.125" below. The lower hole has a lower ratio, yet that's where I get the best pedal and pressure. The problem with using the upper hole is that the brake pedal has a super long throw, and it barely makes 500lbs before hitting the floor. When I do the calculations I get 7.6:1 for the top hole and 5.4:1 for the bottom. Any suggestions? I'm ready to pull out what little hair I have left BTW, this setup is in a '60 Dart. I am running '99 Ram front calipers and '04 Cobra calipers in the rear with a Wilwood 7/8" M/C. Last edited by ab7fh; 07/03/14 04:46 PM. 1970 Dart Resto-Race Project 1960 Dodge Dart Seneca Dual Quad 390 Poly

Re: 800psi enough for manual disc brakes ? [Re: PolyDart] #1290822 07/03/14 09:35 PM 07/03/14 09:35 PM
Joined: Jan 2003 Posts: 27,467 So Cal autoxcuda Too Many Posts
autoxcuda Too Many Posts Joined: Jan 2003 Posts: 27,467 So Cal	Quote: I'm bringing this thread up from the dead because I am having the same issue, but for a seemingly different reason. I am also running a proportioning valve in my rear brake line and I thought that the original poster's fix would be a "voila" moment for me, but no amount of proportioning valve adjustment will give me more than 800psi to the front brakes. The rear brakes are also at 800 psi when allowed to get full flow from the valve. I have played with the pedal ratio. The stock M/C pickup point is 1.5" below the pivot. The hole I drilled is 2.125" below. The lower hole has a lower ratio, yet that's where I get the best pedal and pressure. The problem with using the upper hole is that the brake pedal has a super long throw, and it barely makes 500lbs before hitting the floor. When I do the calculations I get 7.6:1 for the top hole and 5.4:1 for the bottom. Any suggestions? I'm ready to pull out what little hair I have left BTW, this setup is in a '60 Dart. I am running '99 Ram front calipers and '04 Cobra calipers in the rear with a Wilwood 7/8" M/C. What is the diameter of the piston(s) in the front and rear calipers? How many piston in each caliper?

Re: 800psi enough for manual disc brakes ? [Re: autoxcuda] #1290823 07/03/14 11:15 PM 07/03/14 11:15 PM
Joined: Oct 2003 Posts: 21,345 Marysville, O-H-I-O 70Cuda383 Too Many Posts
70Cuda383 Too Many Posts Joined: Oct 2003 Posts: 21,345 Marysville, O-H-I-O	More leverage and more pedal travel equals less line pressure? You sure ALL the air is out? Photobucket sucks

Re: 800psi enough for manual disc brakes ? [Re: autoxcuda] #1290824 07/04/14 01:29 AM 07/04/14 01:29 AM
Joined: Sep 2007 Posts: 876 Arizona PolyDart super stock
PolyDart super stock Joined: Sep 2007 Posts: 876 Arizona	Quote: What is the diameter of the piston(s) in the front and rear calipers? How many piston in each caliper? I called Wilwood shortly after posting this afternoon. He asked about the calipers as well. He's telling me that a 1" bore M/C would be more appropriate for the size pistons I'm running in the Dodge Ram calipers. He said I'm running out of volume and that's why the pedal is catching so low no matter which hole I put the M/C pushrod. 1970 Dart Resto-Race Project 1960 Dodge Dart Seneca Dual Quad 390 Poly

Re: 800psi enough for manual disc brakes ? [Re: PolyDart] #1290825 07/04/14 05:34 PM 07/04/14 05:34 PM
Joined: Jan 2003 Posts: 3,575 The Netherlands BigBlockMopar master
BigBlockMopar master Joined: Jan 2003 Posts: 3,575 The Netherlands	Quote: When I do the calculations I get 7.6:1 for the top hole and 5.4:1 for the bottom. That's 40% more pedalwork you're able to push now. I'm pretty sure you need to go up in size on the MC again a bit to get the proper fluid-displacement and prevent the pedal from bottoming out. BigBlockMopar.com

Re: 800psi enough for manual disc brakes ? [Re: PolyDart] #1290826 07/05/14 12:40 PM 07/05/14 12:40 PM
Joined: Jan 2003 Posts: 28,067 Irving, TX feets Senior Management
feets Senior Management Joined: Jan 2003 Posts: 28,067 Irving, TX	Quote: Quote: What is the diameter of the piston(s) in the front and rear calipers? How many piston in each caliper? I called Wilwood shortly after posting this afternoon. He asked about the calipers as well. He's telling me that a 1" bore M/C would be more appropriate for the size pistons I'm running in the Dodge Ram calipers. He said I'm running out of volume and that's why the pedal is catching so low no matter which hole I put the M/C pushrod. Yep! You've run out of master cylinder. Dig up the brake math spreadsheet and crunch some numbers. I don't have the specs on the calipers but you can probably grab them from product info on Rock Auto. We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon

Re: 800psi enough for manual disc brakes ? [Re: feets] #1290827 07/05/14 03:14 PM 07/05/14 03:14 PM
Joined: Mar 2014 Posts: 40 upper So. CA N ntsqd member
ntsqd member N Joined: Mar 2014 Posts: 40 upper So. CA	For manual brakes I shoot for 93:1 to 95:1 total system ratio for the fronts. then tune in the rears as needed. That is hydraulic ratio multiplied by pedal ratio. Can go over 95:1, but go under 93:1 at your own peril. Below 93 the pedal will rapidly trend towards being rock hard with low line pressure. Above ~100:1 will definitely feel 'mushy.' I used to swerve around my hallucinations, now I drive right thru them.

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